Heart Blocks
also see Dysrhythmias

1stdegree:

• May be normal in athletic people
• asymptomatic
• Constant prolonged PR interval (> 0.2 sec)
• 1:1 conduction
• No treatment

2nd degree:

• Mobitz I: Wenckebach
• Progressive lengthening of the PR interval until a QRS wave is dropped
• Mobitz Type II
  • constant PR interval (may be prolonged or normal) with random dropping of QRS complexes
  • more ominous because can progress to 3rddegree block

3rddegree:

• Complete AV disassociation
• Presentation
• Weakness, Hydrops fetalis, CHF,Syncope, death
• Causes
  • Congenital
    • Structural heart defects
    • Maternal SLE (anti-SSA/Ro and anti-SSB/La antibodies) that cross react with fetal cardiac tissue. -most common, permanent
  • Acquired
    • Lyme disease
    • Cardiac surgery -most common
    • MI
    • Treatment: Pacemaker

CHLA Board Review 2005